Black footed ferret population in Sask. wiped out by drought, plague

The black footed ferret population was reintroduced to Grasslands National Park in 2009, but none of the animals have been spotted there since 2014. 

Stefano Liccioli, wildlife ecologist, and scientist for species at risk with Parks Canada, said consecutive droughts and a non-native disease contributed to the disappearance.

"No ferrets have been detected in the park so our best estimate is that at this moment we do not have ferrets in the park," Liccioli said. 

The animal once lived throughout North America's great plains. It was the only native ferret on the continent and was classified as an endangered animal. 

It was last seen in Canada 1937 and was later thought to be extinct. 

The species was found in Wyoming in 1981 and recovery efforts began throughout North America. In 2000, a recovery strategy for the black footed ferret and a management plan for the black tailed prairie dog were both published. 

Parks Canada started its reintroduction effort at Grasslands National Park in 2009 by releasing 74 animals, with the goal to reestablish a wild population in Canada.

In 2010, wild-born ferrets were observed at the park. Liccioli said it was incredibly significant because it showed that captive-born animals were capable of eventually producing wild litters.

But during the first four years of ferret releases, Grasslands National Park experienced two severe droughts that caused the prairie dog population to decline significantly.

The presence of sylvatic plague — the same bacteria that causes the bubonic and pneumonic plagues in humans — was also detected in the prairie dog population. Both prairie dogs and ferrets are highly susceptible. 

The diet of the black footed ferret consists mostly of black tailed prairie dogs and with the decline of the prairie dog population, the ferrets were at risk. 

In 2013 there were welfare concerns for both species and the decision was made to temporarily suspend any further release of ferrets.

Liccioli said since no ferrets have been detected, Parks Canada and Grasslands National Park are focusing efforts on better understanding prairie dog population dynamics and ecology in general, with contributions from the Calgary Zoo.

Liccioli said the prairie dog population at the park is on par with the long-term average over the past 25 years.

"We also learned that following drought the population will decline. But also, whenever there is good availability of food resources, prairie dogs breed. They have a lot of pups and the population bounces back," said Liccioli. "So we are in the process of seeing how again the population responds to all the different stressors."

Liccioli said there are concerns that climate change will increase the frequency of both droughts and instances of sylvatic plague.

"We're gathering information on prairie dog ecology and population dynamics," said Liccioli. "We are trying to make informed decisions on both prairie dog and ferret recovery."